A man once imprisoned with Iraq's most feared terror leader said Sunday that Abu Musab al-Zarqawi was tortured regularly by Jordanian prison officials in the late 1990s and was held six months in solitary confinement.

Offering possible partial clues as to why the Jordanian-born Al Qaeda leader chose Amman for triple hotel bombings earlier this month, the former cellmate, Yousef Rababaa, said: "He hated the intelligence services intensely, and the authorities didn't know how to deal with his new ideology."

Al-Zarqawi, whose real name is Ahmed Fadheel Nazzal al-Khalayleh, has claimed responsibility for the Nov. 9 suicide attacks in the Jordanian capital that killed 60 people, mostly Muslims.

Reacting with outrage to al-Zarqawi's latest threat — to kill Jordan's king — members of his own family, including a brother and cousin, disavowed him publicly on Sunday.

A U.S. official, meanwhile, said Sunday that efforts were under way to determine if al-Zarqawi was among eight suspected Al Qaeda members killed the day before in a gunfight in the northern Iraqi city of Mosul. The official spoke on condition of anonymity because of the sensitivity of the information. Three of the insurgents detonated explosives and killed themselves to avoid capture, Iraqi officials said.

Rababaa, who spent three years in jail with al-Zarqawi until both were freed under a royal amnesty in 1999, recalled his cellmate's inflexible, radical Islamic ideology.

"He divided the world between Muslim and infidels," Rababaa said, adding that al-Zarqawi was quiet at the time and did not show a violent nature.

"I didn't see that side of him, although he had very strong opinions. I am very surprised at where he is today," said Rababaa, suggesting that maybe someone helps al-Zarqawi plan his terror operations.

"He had very little education, only medium intelligence. But he was very brave," Rababaa said.

He did not specify how he knew al-Zarqawi had been tortured or offer any specific evidence to back the claim.

Jordanian officials were not immediately available for comment but have strongly refuted several other recent claims of torture by other Islamic militants on trial in Jordan's military courts. In its latest worldwide human rights report, the U.S. government also cited what it called "allegations of torture" in Jordan's prisons.

Jordanians, including some who had supported the insurgency against American "occupiers" in Iraq, turned fiercely against the 39-year-old terror leader after the Amman suicide attacks.

Even al-Zarqawi's tribe rejected him, announcing in a statement published in major newspapers on Sunday that they would "sever links with him until doomsday."

"A Jordanian doesn't stab himself with his own spear," the 57 family members wrote.

The statement was a blow to al-Zarqawi, who will no longer enjoy the protection of his tribe and whose family members may seek to kill him.

Al-Khalayleh is a branch of the Bani Hassan, one of the area's largest and most prominent Bedouin tribes, which along with several other tribes form the bedrock of support for the royal family's Hashemite dynasty. Relatives hold senior posts in the army and other government departments.

Al-Zarqawi, who took his name from the city of Zarqa, 17 miles northeast of Amman, often boasted of his family's influence was he was jailed in his native Jordan, Rababaa said.

Rababaa said he debated regularly with al-Zarqawi in prison. Rababaa led a group that advocated purging Muslim lands of foreign occupiers and setting up Islamic states. Al-Zarqawi's group was more fanatical, believing that Islam was worth killing for.

"His way of thinking, in general, is restricted, and he understands Islam with restrictions," Rababaa said. "We had vastly different ideologies."

Rababaa, 36, was serving a life sentence for plotting terrorism against Israeli targets in Jordan when he met al-Zarqawi, who was doing jail time for militant activities aimed at toppling the monarchy.

Rababaa, who has renounced violence, but still advocates an Islamic state, is now a professor of Arabic language at the University of Jordan.

Rababaa said he believes al-Zarqawi will follow through on his threats — made in an audiotape released Friday — to continue attacks on Jordan.

"The problem with this group is that it wants to target any location. It's very hard to control him when he's declared all of Jordan a battlefield."

But he dismissed al-Zarqawi's threat to kill Jordan's King Abdullah II.

"It's words without deeds," he said. "He doesn't seek to topple regimes altogether, but to basically create trouble for the existing regime."

Jordan sentenced al-Zarqawi to death in absentia for planning a terror plot that led to the 2002 killing of U.S. aid worker Laurence Foley. He has claimed responsibility for several other plots in Jordan, including a foiled April 2004 chemical attack.

He also leads a campaign of bombings and kidnappings in Iraq, and the United States has offered $25 million for information leading to his capture.